Cascading dropdowns are returning undefined in mvc

I know this question is on a lot of others here. But here is my issue regarding the matter.

My Json Call in homecontroller:

public JsonResult GetBrand(int id)
{
    List<String> resultdata = new List<String>();

    //get some data via sql query
    using (SqlCommand command = new SqlCommand(query, sqlconn))
    {
        using (SqlDataReader reader = command.ExecuteReader())
        {
            while (reader.Read())
            {
                resultdata.Add(reader.GetString(0));
            }
        }
    }

    return Json(resultdata, JsonRequestBehavior.AllowGet);
}

My 2nd Dropdown’s code:

@Html.DropDownList("Brand", new SelectList(string.Empty, "", ""), "Please select", new { @class = "form-control" })

I also tried:

@Html.DropDownList("Brand", new SelectList(string.Empty, "div_id ", "material_name "), "Please select", new { @class = "form-control" })

And my script:

$(document).ready(function () {
    $("#category").change(function () {
        $.get("GetBrand", { id: $("#category").val() }, function (data) {
            console.log(data);
            $("#Brand").empty();
            $.each(data, function (index, row) {
                console.log(row);
                $("#Brand").append("<option value='" + row.div_id + "'>" + row.material_name + "</option>")
            });
        });
    })
});

On Chrome’s F12 console, I can see this actual list of data I want returned in the dropdown and it is correct (via console.log(row);). However, in the dropdown itself, it shows undefined.

Does anyone have any suggestions to what I am missing?

Answer

This was my fix for anyone also missing something so simple:

                while (reader.Read())
                {
                    items.Add(new SelectListItem
                    {                           
                        
                        Value = Convert.ToString(Convert.ToInt32(reader["div_id"])),
                        Text = reader["material_name"].ToString()
                    });
                }

Now it returns values.